Like most things in this flaming dumpster fire of a nutrition world online, even the most half-baked, bat$hit diet cults manage to accidentally trip over a couple truths -like a drunken raccoon stumbling into quantum physics...

If you missed it, yesterday I broke down why Mark Bell's all-sugar circus act might actually work for a very specific type of human (hint: jacked, trained, enhanced, and in a caloric deficit).

...But before you start chugging corn syrup and calling it science, let’s look at real research here from researchers that weren't snorting Kool-Aid powder—they were measuring actual physiology.

Soap box rant – if I wanted to jump on the bandwagon and sell my left ventricle for the almighty IG likes and comments to steelman the Sugar Diet with science, this is what I would do.

Now, hold on, as after this I’ll put it into actual context since I’d need to leave that part out to keep up my online GooRoo status and bow to the all-powerful algorithm for clicks.

Science Bitches: Acheson et al. (1988)

Yes, 1988 - back to a distant land where time stood still and before cell phones and even the internet itself roamed the earth.

I know it’s hard to believe any good research came from that decade, but these nerds were out here doing amazing work with metabolic chambers while the crew at PF was still eating paste.

Participants

• 12 total subjects (6 lean, 6 obese)
• Age: 23 years (lean), 24 years (obese)
• Sex: Mixed (2 females, 4 males in each group)
• Weight: 69.4 kg (lean) vs 96.1 kg (obese)
• BMI: 21.8 (lean) vs 30.8 (obese)

These were not athletes.

They were described as "healthy, young" adults eating typical Western diets. Nobody was dieting, nobody was medicated, and none of them were on TikTok because it didn’t exist yet.

Study design

• Pre-study: Lean folks consumed a controlled mixed diet (12% protein, 30% fat, 58% carbs) for 3 days
• Overnight fast before testing
• 15-hour stay in a respiration chamber

Intervention: 500 g of carbZ (aka a brick of dextrin maltose)

• 250 g at hour 0
• 125 g at 2 hours
• 125 g at 5 hours All dissolved in 1.2 L of water flavored like fruit sadness.

Measurements

• Continuous gas analysis (VO₂, VCO₂)
• Blood draws every 30 minutes
• Urine collection for nitrogen balance
• Body weight and follow-up checks next day

What they found

Minimal de novo lipogenesis (aka conversion of said carbZ to fat) Even with 500 g of carbs, only 4–5 g of net fat was synthesized. That’s microscopic.

• ~230–240 g of carbs were immediately oxidized
• ~260 g were stored as glycogen
• <1% was converted to fat

Respiratory quotient (RQ) RQ rose to 0.95–1.00 for 8 hours, showing near-total carb oxidation.
Side note, while RER and RQ are not the same thing, they are close enough here to describe what fuel was being used (aka oxidized).

Let me translate that for my fellow meathead: the body took this carb tidal wave, absorbed it, torched a bunch immediately, and stashed the rest as usable glycogen fuel.

Barely any fat gain, even with a half kilo of carbs smashed into their gullets.

Key points

• Even in sedentary people, the body handled 500 g of carbs like a boss
• Most of it went to glycogen and immediate energy
• DNL was barely a blip on the radar
• If these non-athletes didn’t get fat off 500 g of carbs, your squatting, sled-pushing ass sure as hell won’t either—especially if you’re training hard and healthy

Now, before you sprint to the kitchen to chug maple syrup and declare victory over the laws of thermodynamics, let me rain on this carb parade with some context.

Counterpoint aka Context: Sugar ain't magic, Brosefus

· Yeah yeah, I get it—the Acheson study is beautiful. You shovel 500g of pure carb powder into some hooomans and boom—barely any turns into fat. Cue the metabolic fireworks and victory laps on Reddit.

But before you start mainlining pixie sticks and calling it science, let me hit you with a flaming fist of context.

First off—this wasn’t real life. They gave people liquid carbs in a lab. No fat.

No protein.

No pizza.

No donuts.

Just a big warm jug of Dex-cocaine in water. Try mixing your daily sugar load with 40g of fat and see what happens.
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Spoiler: de novo lipogenesis stops being a cute science term and becomes your actual ass.

Second—acute ≠ chronic, you carb-drunk raccoon Sure, in a 15-hour window, DNL barely budged.

…But what happens when you hammer 500g of sugar every day for a month like a cracked-out hummingbird? Yeah, glycogen tanks fill up. Then what? Overflow mode.
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Body fat starts creeping like a dude at a yoga class in camo cargo shorts.

Third—these weren’t insulin-resistant TikTok zombies. The subjects were lean-ish, young, and probably metabolically flexible. You think the average inflamed, desk-bound keyboard warrior can pull that off without some metabolic blowback? You must be tripping on glucose syrup fumes.

Fourth—glycogen isn’t infinite, Einstein Most people have room for maybe 400–600g of glycogen on a good day. Smash past that, and your liver’s like “bro I’m full” while your fat cells are rubbing their hands together like cartoon villains.

And finally—being lean isn’t the only health metric, my sugar-soaked friend. Chronically spiking insulin and blood glucose all day long—even if you don’t get fat—can still mess up energy regulation, sleep, cravings, mood, and the dark abyss of long-term health. I’ve seen it.

Clients living on sugar and prayers—wrecked HRV, trash sleep, mood swings like a caffeinated barn owl.

Context, you beautiful bastard

If you’re metabolically flexible, have decent muscle mass, train regularly, and maybe dabble in a few anabolic compounds, yes—the sugar diet might “work.”

But if you’re under-muscled, undertrained, metabolically inflexible, and your idea of cardio is yelling at strangers on Reddit, slamming 600 g of sugar a day is going to end badly.
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If your buddy’s ass has the consistency of a throw pillow from a 1983 Buick Regal, and his glycogen stores haven’t been even slightly dented since Reagan was yelling at the Berlin Wall, and his blood is basically hummingbird nectar at this point—don’t expect his body to handle 500 grams of sugar like a jacked-up Tour de France mutant.
​
Metabolic flexibility ain’t built on Mountain Dew, memes, and high school dreams.

Long-term is this Sugar Diet the best idea?

Heck no!

By all means, if you are metabolically flexible eat more carbZ, but also include much more protein and more fat than the Sugar Diet GooRoos who claim 100 gram of protein and 30 grams of fat is enough.

You’d be far better off adding some protein, veggies, and a bit of fat to support.

Even a cracked-out Cuckoo clock that’s been huffing ketone salts and screaming about insulin at 3am is still right twice a day—so yeah, the Sugar Slingin’ GooRoos accidentally tripped over a tiny sliver of metabolic truth here.

….but just because they nailed one half-baked idea in the middle of their glycemic fever dream doesn’t mean the whole sugar-drenched circus act belongs in your mouth or your macros.

Bottom line: The sugar diet crew accidentally found some real metabolic truth buried under their pile of pixie sticks, however, context is everything, and nuance doesn't get clicks.

Part 3 drops tomorrow with the actual game plan—how to fuel your training, optimize your metabolism, and avoid both the sugar-drunk extremes and the carb-phobic nonsense.

Until then, keep your protein high, your training consistent, and your critical thinking skills sharper than your mom’s kitchen knives.

Much love,

Dr Mike

PS- if you want to go super indepth on all things nutrition for performance and better body comp, the Flex Diet Cert will open again on June 16, stay tuned.

Reference
Acheson KJ, Schutz Y, Bessard T, Anantharaman K, Flatt JP, Jéquier E. Glycogen storage capacity and de novo lipogenesis during massive carbohydrate overfeeding in man. Am J Clin Nutr. 1988 Aug;48(2):240-7. doi: 10.1093/ajcn/48.2.240. PMID: 3165600.

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Mike T Nelson CISSN, CSCS, MSME, PhD
Associate Professor, Carrick Institute
Owner, Extreme Human Performance, LLC
Editorial Board Member, STRONG Fitness Mag

Mike T Nelson is a PhD and not a physician or registered dietitian. The contents of this email should not be taken as medical advice. It is not intended to diagnose, treat, cure, or prevent any health problem - nor is it intended to replace the advice of a physician. Always consult your physician or qualified health professional on any matters regarding your health.

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